Air-box with grille



Dec. 12, 1961 W- V^N EKERE" 3,012,493 AIR-BOX WITH-GRILLE l Filed Jan. 21, 1958 2 Sheets-Sheetg1 Dec- 12, 1951 w. VAN EKL-:REN

AIR-Box WITH Gams 2 Sheets-Sheet 2 Filed Jan. 21, 1958 lUnited States Patent Ohtice 3,012,493 AIR-BOX WITH GRILLE Willem van Ekeren, The Hague, Netherlands, assigner to N.V. Nederlandsche Airconditioning MIJ Gebr. van Swaay, The Hague, Netherlands, a Dutch limitedliability company Filed Jan. 21, 1958, Ser. No. 710,352 Claims priority, application Netherlands Jan. 22, 1957 2 Claims. (Cl. 98-40) The invention relates to an air-box or air-conduit section providedr with a grille or louvre or grid through which air is delivered, distributed and controlled in a ventilation or air-conditioning system, in which the grille is made as a perforated panel. Many types of such grilles are well known already. They are different from grilles consisting of lattice-work, which may or may not cornprise vanes.

In general, grilles of the type referred to are constructed in such a way that the air outlets are uniform in form, position, and direction all over the grille. The air jets produced by each of the perforations flow together to form a single air stream, in the same way as with latticework grids.

Such a combined air current shows only a fairly low induction, i.e. it carries along only a small amount of room air (secondary air), and consequently mixes only slightly with this room air, so that its energy decreases only slowly. In view of this it will penetrate far into the room if the blow-off pressure, and accordingly the blow-off velocity, is not kept low.

In this connection the term blow length is used, i.e. the distance traversed by the air stream from the grille to a point where the velocity of the air, measured at the center of the current, has been reduced to a rate of l inches per/sec. This blow length has to be small if no unpleasant draughts are to be created in the room.

It is therefore advantageous to keep the injected air subdivided as much as possible into separate jets, because such jets show great induction, i.e. carry along a large amount of ambient air and mix therewith, as a result of which the blow length is also greatly limited. It is then possible to operate with great differences in temperature and humidity respectively between the injected air and the air in the room without this being unpleasant to the occupants of the room. Great differences in temperature make it possible to keep the quantity of the air to be iniected relatively small, in consequence of which a relatively narrow and thus inexpensive piping system can be used.

The admissible blow length is dependent on the shape of the room in which the grille is mounted, and more particularly also on the location of the grille in the room in question. The greater the distance of the wall of the roorn opposite the grille from the latter, the greater the blow length that can be applied. Local adaptation of the blow length is therefore desirable.

The above is achieved according to the invention by the fact that the perforated panel of which the blow-off grille consists is divided into a number of separate, preferably individually exchangeable plates, all the perforations in one plate being equally directed, i.e. giving the same direction to the air jet produced, but at least two of the plates differing from one another as to the direction of their perforations.

After the grille has been mounted, it is still possible to exchange some of the plates or` if desired, all the plates in order to obtain an adaptation of the airstreams produced to the room. If the grille is located in a corner of the room or if the room has an asymmetrical shape, an asymmetrical blow-ott pattern can also be obtained.

3,912,493 Patented Dec. l2, 1961 The only thing needed is that the separate plates with dilerent blowing directions of the perforations are available.

It has been found that upon application of the invention temperature differences of 15 C. and more between the injected air and the air in the room are admissible.

It is desirable for as high a static pressure as possible to be attained behind the grille, in order to obtain as powerful an etiiuence as possible, uniformly distributed over the grille, so as to insure a high induction. To achieve this, the energy of ow of the air supplied has to be converted into static pressure as far as possible. With a view to this the end of the supply conduit in the chamber is provided with blades disposed in the form of a fan, with spreading in the longitudinal direction of the grille.

If these blades are made readjustable, the occupant of the room will himself he able to control the air volume, and consequently the temperature in the room.

The drawing illustrates an embodiment of the invention.

FIG. l is a horizontal cross-section of an air-box with a blow-off grille.

FIG. 2 is a front elevation of this box.

FIG. 3 is a cross-section of one of the plates of the grille.

FIG. 4 is a similar cross-section to FIG. 3 of a grille plate in which the perforations have a ditferent direction.

The Walls and bottom 1 of the boX are made of sheet metal or plastic. In general the box has a rectangular shape. The walls and the bottom are lined on the inside with insulating material 2, which provides thermal insulation as well as sound-dampening.

The front of the box consists of four readily exchangeable grille plates 3, 4, 5 and 6. FIG. 3 shows a crosssection of the plate 3 having nozzles N possibly of varying cross-section (i.e., the nozzles may be conical), the bores B of which have an axial cross-section adapted to the formation of a jet. In the case of FIG. 3 they include an angle of 30 with the direction perpendicular to the plate. If the box has been mounted approximately symmetrically against a wall of a room, the plates 3 and 4 will be constructed according to FIG. 3 and the plates 5 and 6 similarly, but with the perforations directed in the opposite sense, i.e. to the right in FIG. l.

If the box has been mounted asymmetrically in a room, one or more of the plates 3, 4, 5 and 6 will be constructed according to FIG. 4, with perforations directed more along the normal or perpendicular direction to the plate.

It is possible to have plates with differently directed perforations available. It has been found very suitable to have plates available whose perforations include angles of 0, 12.5, and 30 respectively with the normal.

It is obvious that even when a box as illustrated has already been mounted in a room, it is still possible to exchange one or more of the plates 3, 4, 5 and 6, in order to adapt the direction and the blow length of the ejected air to the room.

The air to be introduced is supplied from an air channel system through a conduit 8, which has been connected in the center to the rear wall of the box. This rear wall comu-rises a divergent nozzle 9 directed towards the interior of the box. Mounted in diverging directions inside this nozzle, for guiding incoming air in substantially opposite directions, are two blades 10 and 11, which are adapted to pivot about the axes 12 and 13. By means of coupling rods 14 and 15 these blades are connected with a nut 16, adapted to move on a screw spindle 17. The screw spindle 17 is movably supported in the box by bearings 18 and 19, and the spindle is provided at itsy end with ar knob 20 extending outside the box. By means of this knob 2t) the screw spindle 17 can be turned, as a result of which the blades 10 and 11 can acquire a different inclination. The position shown in the drawing is one. extreme position and the position 21 in dotted' lines isA the` other extreme, positionfor the blade 11.

Readjustment of the blades makes it possible to con.- trol the volume. In the position 2,1 shown indotted lines the air supply is even blocked completely, because the blade rests at: one end against4 the nozzle 9 and. at the other end against the part of` the, Wall. 22Y in which the screw spindle 17 is, movablyr supported. It will be understood that the shape of the blades has been so chosen that even upon readjustment the air continues to be guided in such a way that the resistance offered` to the air tlow is as small as possible and the supply velocity is converted into static pressure as far as possible in the air-box. The bailles 23 and 24 provide as uniform a distribution of the air as possible over the grille'plates 3, 4, and 6.

What is claimed is:

1. An air-box adapted to be connected to an air channel system for the supply of conditioned high-pressure air, said air-box comprising a casing, said casing comprising a front wall including a grille and a back wall having an inlet adapted to be connected to the air channel systernan adjustable air deflection and control means inside the casing and opposite said inlet including a divergentv nozzle for guiding the incoming air in substantially opposite directions within said casing, said grille includf ing a plurality of separate plates of substantially identical shape individually mounted* and interchangeably on the casing, each of said plates being provided with a plurality l of nozzles constituting air outlets and having bores adapted to form jets of air, the nozzles being spaced in order to allow free access of ambient air around each jet of air escaping yfrom the bores, all bores in each one of the said plates being parallel and at the same langle to the surface of the associated plate, the bores of the nozzles on one of said plates being arranged at a different angle with respectA to the latter said one plate than the bores of the nozzles on another of said plates with respect to the latter said other plate.

2. An air-boxv according to claimV 10, wherein said air deflection means further comprises, two blades pivotally mounted inside of said nozzle for opening and closing said nozzle, said blades dividing the incoming air into separate parts, baffles between the nozzle and the'grille, a screw spindlesupported on said casing and being accommodated on the center line of but outside of the nozzle, and means cooperating with said spindle and coupled to said blades for adjusting the position thereof in order to control the amount of incoming air, said spindle being manually operable from outside of the grille. i

lReferences Cited in the le ofthis patent UNITED STATES PATENTS` 2,116,873 Williams May 10, 1938 2,182,690. Cole Dec. 5, 1939 2,320,007 Otto May 25, 19413v 2,528,130 Frisket'al Oct. 31, 1950 2,621,579 Person et al Dec. 16, 1952 2,644,389Y Dauphinee July 7, 1953 2,711,087- lennings June 21, 1955 2,835,187 Schell May 20, 1958l 

